Ignition coil



J1me 1945- E. E. ROBINSON ET AL 2,373,791

IGNITION COIL Filed Dec. 6, 1943 Fi g2 INVENTORS. 6M 6 am fflmm e M ATTORNEY Patented June 19, 1945 7 IGNITION COIL Eric Ernest Robinson and Edward William Jack Barrington, Wlllesden Junction, London, England, assignors to Rota: Limited, London, England Application Decmber 8, 1943, Serial No. 513,120 In Great Britain October 3, 1942 3 Claims.

This invention relates to ignition coils used in the spark ignition systems of internal combustion engines, and of the type in which oil is used for insulating the secondary windings, the

object of the invention being to provide an improved construction enabling oil-insulation oi the secondary windings of such coils to be eiiected more satisfactorily than heretofore.

The invention comprises a construction in which the secondary winding is separated in a fluid-tight manner from the primary winding by a layer of impervious flexible material having its edges sealed to end flanges between which the primary and secondary windings are situated, and in which an impervious layer is provided around the exterior of the secondary winding, this layer also having its edges sealed to the said end flanges.

In the accompanying drawing:

Figure 1 is a sectional side elevation, and Figure 2 a sectional end elevation taken on line 22 of Fig. l (with the primary and secondary windings omitted), of an ignition coil embodying the invention.

In carrying the invention into eflect as shown, we mount on an iron core a of any convenient construction a pair of flanges b made from any convenient insulating material, and at the inner face of each flange we provide a central collar which is either sealed to the adjacent flange by any convenient adhesive or is formed integrally with the flange. The flanges b are secured to the core through the medium of brass strips (1. the latter being secured to the flanges and core in any convenient manner. The diameter of the collars c is such that they form with the core a an annular recess of sufficient size to accommodate the primary winding e. After this winding has been arranged in position it is enclosed by a layer of impervious flexible material I, such as oiled silk, and the edges of this layer are sealed to the peripheries of the collars c by any convenient oil-resisting adhesive. The secondary winding a and its interlayers h of paper or other insulating material are then arranged in position around the primary winding e and between the nanges b in the usual manner. Subsequently the secondary winding a is secured and enclosed by a layer or layers 2 of cambric tape or any other convenient material, the peripheral portions of the flanges being shouldered and grooved as shown to accommodate the edges of this layer or layers. Finaiiy rwe apply to the layer or layers i an outer layer 7' or impervious material. This material may consist of synthetic rubber and it is preferably applied in the form of a paint, care being taken that it not only eifectiveiy encloses the outer surface of the cambric binding, but also forms an efiective seal between the ends of this binding and the flanges. Alternatively this outer layer may be applied in sheet or strip form, its edges being sealed to the flanges by synthetic rubber solution or other suitable adhesive. In either case, the outer layer is subsequently vulcanised.

The oil required for insulating the secondary winding 0 is then introduced through a hole k in one o! the flanges b in the usual manner, and the hole is subsequently sealed.

By constructing a coil in the manner above described we are able to obtain a strong oiltight construction which is capable of withstanding without risk or oil leakage large variations of pressure which may result from heatin or variations of atmospheric pressure, the construction being consequently well adapted for efiective service on air-craft engines.

Having thus described our invention what we claim as new and desire to secure by Letters Patent is:

1. An ignition coil comprising a metallic core, a pair of spaced radially extending flange members of insulating material surrounding and secured to said core, said flange members having oppositely disposed internal shoulders, a primary winding wound on said core inwardly of said shoulders, a flexible impervious layer surrounding said winding and having the edge portions thereof sealed to the peripheral surfaces of said shoulders, a secondary winding wound on said flexible layer, a covering of fabric such as cambric tape around said secondary winding and engaging a pair of grooved internal shoulders on said flange members, and a layer of vulcanized flexible rubber-like material surrounding said covering and having fluid-tight sealing engagement with said flange members, whereby said secondary winding is enclosed in a fluidtight chamber.

2. An ignition coil comprising a pair of spaced end members, each of said members having two radially spaced internal shoulders, a flexible oil impervious layer extending between said members and having its edge portions sealed to oppositely disposed shoulders on said members, a winding surrounding said layer, and an impervious layer surrounding said winding and having its edge portions in fluid-tight engagement'with the other oppositely disposed shoulders on said end members.

3. An ignition coil 01 the type specified in exterior or the secondary winding having its which the secondary winding is separated in a edges sealed to the said end flanges, and in fluid-tight manner from the primary winding by which the inner face or each flange is provided a layer of impervious flexible material having its the adjacent edge of the separating layer is edges sealed to end flanges between which the 5 sealed. primary and secondary windings are situated, in ERIC ERNEST ROBINSON. which an impervious layer is provided around the EDWARD WILLIAM JACK BARRJNG'ION.

Certificate of Correction Patent No. 2,378,791 June 19, 1945 ERIC ERNEST ROBINSON ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Page 2, second column, line 3, after the word provided insert with a central collar to the periphery of which;

and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Ofiice.

Signed and sealed this 12th day of September, A. D. 1950.

THOMAS F. MURPHY,

Assistant Oommiuioner of Patents. 

